1. Field of the Invention
The present invention relates to a feeding device, and more particularly to a feeding device for a caulking gun.
2. Description of Related Art
With reference to FIGS. 4 and 5, a conventional feeding device for a caulking gun in accordance with the prior art comprises a frame (50), a handle (51), a trigger (52), a plunger shaft (60), a drive grip (53) and a brake grip (54). A first recess (501) and a second recess (502) are defined in the frame (50). The handle (51) extends outward from the frame (50) below the second recess (502). The trigger (52) is pivotally mounted in the frame (50) forward of the handle (51). The plunger shaft (60) extends through the frame (50) and penetrates the drive grip (53) in the first recess (501) and the brake grip (54) in the second recess (502). The drive grip (53) and the brake grip (54) each has a through bole (not numbered) allowing the plunger shaft (60) to extend through the grips (53, 54). The diameter of the through holes in the drive grip (53) and the brake grip (54) are slightly larger than the diameter of the plunger shaft (60). A pin (521) is attached to one end of the trigger (52) and extends into the first recess (501) to push the drive grip (53). The drive grip (53) is inclined to the plunger shaft (60) for engaging with the plunger shaft (60) and driving the plunger shaft (60) forward to squeeze out the caulking compound when pushed by the pin (521) which is attached to the trigger (52). A first compression spring (531) is mounted around the plunger shaft (60) between the forward wall of the first recess (501) and the drive grip (53) to provide a restitution force to return the drive grip (53) and the trigger (52) back to a position to begin the next compression stroke. A groove (503) is defined in the top of the second recess (502), and a through hole (504) is defined in the rear wall of the second recess (502). The top edge of the brake grip (54) is held in the groove (503), and the other end extends down and aligns with the through hole (504). A second compression spring (541) is mounted around the plunger shaft (60) between the forward wall of the second recess (502) and the brake grip (54). The second spring (541) presses the brake grip (54) to selectively engage with the plunger shaft (60) and allow the plunger shaft (60) to move forward only.
With reference to FIGS. 4, 5 and 6, a button (55) is mounted in and extends through the through hole (504) in the rear wall of the second recess (502) in frame (50). The button (55) is pressed to push the brake grip (54) forward perpendicular to the plunger shaft (60) to release the plunger shaft (60) so that the plunger shaft (60) can be pulled back and the caulking gun can be loaded again.
The caulking compound for use with the caulking gun is in a tube. The tube has a nozzle that has a diameter smaller than that of the tube, and the caulking compound has a high viscosity and is slightly compressible so the pressure on the caulking compound in the tube is not immediately relieved when the plunger shaft (60) stops pressing the caulking compound. Rather, the caulking compound continues to squeeze out of the tube until the pressure stored in the caulking compound in the tube is fully relieved. Consequently, the caulking compound is wasted with too much caulking compound being applied to the parts being caulked or polluting the environment.
The present invention has arisen to mitigate and/or obviate the disadvantages of the conventional feed device for a caulking gun.